In a heavy non-aluminum skillet, heat the bacon grease and saute the green onions, celery and garlic until the onions are clear and soft. Add oysters, thyme, salt, cayenne, black pepper, paprika and lemon juice to the pan and cook for an additional 3 to 4 minutes. Stir in flour and when bubbly, add cream and oyster liquid. Cook ingredients until thickened. Stir in parsley.